Now that I have done a bit of brazing practice, and have found a way to prevent the copper-oxide from forming inside the brazed refrigeration lines, I think I'm all ready to go. I have my heat exchangers ready and it's time to strip down the AC unit and see how everything's going to fit up.
If you haven't tackled anything like this before, it's good to cultivate a calm and peaceful mind before beginning.
I like to get a hot cup of tea, a notebook to take notes in, a digital camera to take photos for future reference, and maybe even post a blog.
So find a fairly sturdy surface to put the AC unit on that is at a comfortable height. Since my workshop isn't very much bigger than a phone booth, I set the AC unit on my little freezer.
You'll need a phillips screw driver with a plastic handle and some pliers, preferably with plastic-covered handles, to get most everything apart.
(* MAKE SURE THE AC UNIT IS NOT PLUGGED IN *)
First we carefully remove the metal and plastic panels. I like to save all the screws in a jar lid either for re-assembly or future projects. If a panel refuses to come off, there's most likely a screw hiding somewhere. Be patient, don't force anything.
So the bottom pic shows my AC unit minus the panels.
So, take a few minutes to just look at the unit from all angles. After all, you paid good money for this thing (I think I paid $25), and it may never look this way again...
One of the ideas I like to consider is
the possibility of obtaining the maximum amount of benefit with the minimum amount of modification...
In my case, I have decided to make a water-to-water heat pump out of an ait-to-air cooling device, so the modification will be significant.
But we could make an air-to-water device to pre-heat water for a water heater. If we went that route, we could leave almost all of the unit intact and just replace the condenser (the tubing with the fins on the back that get hot when the AC unit is running). We'd still have to extract the refrigerant, cut out the existing condenser, and braze in a refrigerant-to-water heat exchanger. We'd also probably want to remove the rear fan, since it would no longer have a function.
There are other possibilities too, to be considered.
(* EYE PROTECTORS SHOULD BE WORN FOR THE NEXT SECTION *)
Now let's look for the capacitor. It's usually silver, about the size of an orange juice can, and has wires sticking out of the top. The purpose of the capacitor (AKA: 'cap') is to store electricity for the compressor and motor to start. There's a good chance that the cap still has enough voltage stored in it to give you a nasty shock.
(* The reason for the eye protection is that if you get a shock, the tool you are holding could get involuntarily jerked in the direction of your face *) Get a plastic handled screw driver and short the connectors together. There are usually three of them so it may take a bit of finagling...
Now we are going to carefully remove the wiring assembly. They are all different, so I can only give general directions.
On top of the compressor, is a plastic cap with a small nut holding it on. Get a small wrench or pliers and remove the nut, and the washer under it. As you remove the nut, notice how much force was required to remove it, usually not very much... remember that because when you put it all together, you won't want to use too much force. Put the nut & washer in the same place you carefully put all the screws. Now carefully remove the plastic cap. You should see something like this:
Your wires might be a bit different. This is the time to get the digital camera out and photograph the wire positions, from several different angles. Also a good time to get the notebook and draw a picture of the wire positions, including any little letters that may be printed near the wire terminals and the colors of the wires that attach there. I promise you that there will come a time when you will want
both the photo and the detailed drawing. Now it's time to remove those wires. This is where the rubber-handle pliers come in. Did you already short out the cap? Because some of the wires from the cap go to the compressor... So firmly but gently grip the connectors and pull straight up, one at a time.
Some of the wires will go to the capacitor, which might be out in the open. So, you will want to pull those wires too, but not before you make a photo and do a drawing, labeling any colors and markings on the cap for future re-assembly.
Also, some of the wires will go to the switches on the AC unit. It's time to remove any screws that holds the switch. There will also be a tiny tube from the switch that goes toa little tab in the front of the evaporator the part that gets cold when the AC is running.
At this point, most all of the wiring should be easy to remove, maybe a screw or two, but it should come right off...
Here's what my wireing assembly looks like.
It would probably be a good idea to put the plastic cap and washer and small nut back on the compressor and snug it down, so it doesn't get lost.
So, here's the compressor minus the wires:
Notice the small coil of very thin tubing that is near the bottom of the compressor...
This tiny coil is called the 'cap tube', no relation to the capacitor...
This tiny coil is very delicate and serves the purpose of precisely metering the refrigerant from the condenser (hot part) to the evaporator (cold part). We will need to re-use this delicate part, so be very careful with it, don't bend it if you can possibly avoid it, and if you kink it, then
GAME OVER. We will be cutting the tube somewhere around the yellow marks, but that will be a bit later. For now, be very careful around the cap tube.
(* * * * more to follow * * * * )
Regards,
-AC_Hacker
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